1. Field of the Invention
The present invention relates to tube-fitting assemblies and, more particularly, to a tube-fitting assembly having a double-bead and a sealing member so that the assembly remains sealed under relatively high temperatures.
2. Description of Related Art
Tube-fittings are known which provide a fluid tight seal and permit many disassemblies and reassemblies which effectively reseal each time. A first type of tube-fitting commonly used in the prior art is one wherein a nut is slipped over the end of the tubing and then a sleeve with two conically tapered ends is slipped over the end of the tube. The tube end is then inserted in a second coupling member which has an annular lateral shoulder at about a 45 degree angle to the tube axis. The nut also has a 45 degree angle shoulder. The two shoulders axially compress the conical sleeve to provide a seal between the sleeve and the tube.
A second type of tube-fitting assembly is a single-bead or double-bead tube-fitting. U.S. Pat. No. 4,871,199, which is expressly incorporated herein in its entirety by reference, discloses a double-bead tube-fitting. With this type of tube-fitting the conical sleeve of the first type of tube-fitting is replaced by one or more beads formed in the tube. Lateral shoulders on first and second fittings compress the beads to provide a seal between the beads and the fittings.
Each type of tube-fitting, however, may fail under relatively high temperatures. For example, gas tubing connected directly to some sealed burners of a gas stove may fail if the burner at the tube fitting connection exceeds a certain temperature. Some sealed burners may reach temperatures of up to and over 500 degrees Fahrenheit. At this temperature leaks may occur because the tube-fittings may relax. Accordingly, there is a need for a tube-fitting that remains sealed at relatively high temperatures where components of the tube-fittings may relax.